The present invention relates to a novel lithographic rinse solution that decreases defects and pattern-falling, when used for rinsing the photoresist after the image-forming light-exposure and the development, and is effective for shortening rinsing treatment time by improving a draining speed, and relates to a method for forming a patterned resist layer by using the lithographic rinse solution.
In recent years, a light source for fine working has been changing to a shorter wavelength capable of forming a higher-resolution patterned resist layer with the compactness and integration of semiconductor devices; specifically, changing from ordinary ultraviolet light to the g-line (436 nm), from the g-line to the i-line (365 nm), from the i-line to KrF excimer laser beams (248 nm); and currently, to ArF excimer laser beams (193 nm), F2 excimer laser beams (157 nm), and further to electron beams such as EB and EUV, which now have become the major current. In order to follow up the trend, a process and photoresist material compliable with these short-wavelength light sources are under development at a fast pace.
Conventional photoresists are required to have; for instance, satisfactory sensitivity, pattern resolution, heat resistance, focusing depth latitude; an improved cross sectional profile of a patterned resist layer resulting therefrom; improved aging stability after having been coated resulting in the deterioration of the shape of the patterned resist layer due to contamination with amine and the like in a period between the steps of light exposure and post-exposure baking (PEB); and substrate dependency, which means the phenomenon that changes are caused in the cross sectional profile of the patterned resist layer depending on various coating films on the silicon wafer such as an insulating film including silicon nitride (SiN) films, semiconductor films including polycrystalline silicon (poly-Si) films and metallic films including titanium nitride (TiN) films. These requirements have been solved to some extent, but a defect which is a particularly important issue has many problems remaining unsolved.
The defect means a mismatch between a patterned resist layer and a patterned photomask, which is detected when a patterned resist layer after having been developed is examined from right above with a surface defect observation instrument, for instance, the mismatch like a difference between shapes of the resist patterns, occurrence of scums and contaminants, irregular coloring and coalescence between the patterns. The yield of the semiconductor devices decreases as the number of defects increases so that, even through the photoresist has the adequate resist characteristics as described above, defects make it difficult for the semiconductor devices to be mass produced, while the problems thereof remain unsolved.
Various causes for the defect can be considered, some of which are the production of microbubbles in the developing step, and the re-deposition in the rinsing step of once removed insoluble substance.
As a method for decreasing such a defect, an improving method of changing the composition itself of a positive-working resist used in pattern formation (JP2002-148816A) is proposed, but such a change of the composition is not preferable because the process itself need be changed.
A method of applying a compound containing a hydrophobic group and a hydrophilic group, which is a surface active agent, in the formation of the patterned resist layer is also proposed (JP2001-23893A), but the method has a problem of making the top of the patterned resist layer round to lower the orthogonality in the cross sectional profile, and further of film thickness reduction of the resist layer during the treatment. Besides, the method has to select a surface active agent so as to match a resist to be used, which makes an operation complicated, because a semiconductor manufacturing plant supplies a developer solution used for development treatment usually through a collective pipeline, accordingly, when using various resists, it is necessary to change the treatment agent in correspondence to each resist, and to clean the inside of the pipeline after each run. Consequently, the above-described method is unsuitable for a practical application.
Furthermore, a method of reducing the defects by using a developer solution containing an organic base with no metallic ions and a nonionic surface active agent as the main component, in a development step of photolithography (JP2001 -159824A), and a method of reducing the defects by treating the exposed photoresist layer before post-exposure baking treatment, with the use of an aqueous solution having a pH of 3.5 or lower which contains low-volatile aromatic sulfonic acid with a molecular weight of 200 or more (JP2002-323774A), are known but show no sufficient effects.
On the other hand, a method of using the composition of a rinsing agent containing a nitrogen-containing compound with a molecular weight of 45 to 10,000, which has an amino group or an imino group, and a hydrocarbon group with 1 to 20 carbon atoms in the molecule, so as to inhibit falling and damage of a patterned resist layer occurring in a rinsing step and a drying step (JP11-295902A) is also known, but the method of using such a composition of a rinsing agent cannot reduce the above-described defect. Besides, a rinse solution containing an ethylene oxide-based or propylene oxide-based surfactant (JP2004-184648A) is known, but such a rinse solution cannot inhibit a pattern falling because the hydrophilic group has weak interaction with water.